.NET Framework 4.6 and 4.5
Occurs when the communication object first enters the closing state.
(in System.ServiceModel.Primitives.dll) System.ServiceModel
event EventHandler Closing
This event occurs when the communication object first begins to transition from the Opened state into the Closed state, immediately after either the Close or BeginClose method is invoked.
Supported in: 4.6, 4.5, 4, 3.5, 3.0
.NET Framework Client Profile
Supported in: 4, 3.5 SP1
.NET for Windows Phone apps
Supported in: Windows Phone 8.1, Windows Phone Silverlight 8.1, Windows Phone Silverlight 8
Portable Class Library
Supported in: Portable Class Library